Currently, there is an increasing concern for a display device with an extra large screen. In application scenes like a public square, a dispatching center, a surveillance center, a common center, a conference room, a broadcast room, an exhibition room, a party background, a shopping center, there is a common need for an extra large screen, and there is also a requirement for an increased size of the screen. However, due to limitations of processes and product cost, the display screen of a single display module generally is not larger than 60 inches. Therefore, light emitting diodes (LEDs) or tiling is usually used to realize a display device with an extra large screen. Since the display device with an extra large screen which is realized by LEDs generally has a low resolution, the tiling technique has been applied widely. In the tiling technique, display modules are tiled to provide a display device with an extra large screen.